1#ifndef _LINUX_ELEVATOR_H 2#define _LINUX_ELEVATOR_H 3 4#include <linux/percpu.h> 5 6#ifdef CONFIG_BLOCK 7 8typedef int (elevator_merge_fn) (struct request_queue *, struct request **, 9 struct bio *); 10 11typedef void (elevator_merge_req_fn) (struct request_queue *, struct request *, struct request *); 12 13typedef void (elevator_merged_fn) (struct request_queue *, struct request *, int); 14 15typedef int (elevator_allow_merge_fn) (struct request_queue *, struct request *, struct bio *); 16 17typedef void (elevator_bio_merged_fn) (struct request_queue *, 18 struct request *, struct bio *); 19 20typedef int (elevator_dispatch_fn) (struct request_queue *, int); 21 22typedef void (elevator_add_req_fn) (struct request_queue *, struct request *); 23typedef int (elevator_queue_empty_fn) (struct request_queue *); 24typedef struct request *(elevator_request_list_fn) (struct request_queue *, struct request *); 25typedef void (elevator_completed_req_fn) (struct request_queue *, struct request *); 26typedef int (elevator_may_queue_fn) (struct request_queue *, int); 27 28typedef int (elevator_set_req_fn) (struct request_queue *, struct request *, gfp_t); 29typedef void (elevator_put_req_fn) (struct request *); 30typedef void (elevator_activate_req_fn) (struct request_queue *, struct request *); 31typedef void (elevator_deactivate_req_fn) (struct request_queue *, struct request *); 32 33typedef void *(elevator_init_fn) (struct request_queue *); 34typedef void (elevator_exit_fn) (struct elevator_queue *); 35 36struct elevator_ops 37{ 38 elevator_merge_fn *elevator_merge_fn; 39 elevator_merged_fn *elevator_merged_fn; 40 elevator_merge_req_fn *elevator_merge_req_fn; 41 elevator_allow_merge_fn *elevator_allow_merge_fn; 42 elevator_bio_merged_fn *elevator_bio_merged_fn; 43 44 elevator_dispatch_fn *elevator_dispatch_fn; 45 elevator_add_req_fn *elevator_add_req_fn; 46 elevator_activate_req_fn *elevator_activate_req_fn; 47 elevator_deactivate_req_fn *elevator_deactivate_req_fn; 48 49 elevator_queue_empty_fn *elevator_queue_empty_fn; 50 elevator_completed_req_fn *elevator_completed_req_fn; 51 52 elevator_request_list_fn *elevator_former_req_fn; 53 elevator_request_list_fn *elevator_latter_req_fn; 54 55 elevator_set_req_fn *elevator_set_req_fn; 56 elevator_put_req_fn *elevator_put_req_fn; 57 58 elevator_may_queue_fn *elevator_may_queue_fn; 59 60 elevator_init_fn *elevator_init_fn; 61 elevator_exit_fn *elevator_exit_fn; 62 void (*trim)(struct io_context *); 63}; 64 65#define ELV_NAME_MAX (16) 66 67struct elv_fs_entry { 68 struct attribute attr; 69 ssize_t (*show)(struct elevator_queue *, char *); 70 ssize_t (*store)(struct elevator_queue *, const char *, size_t); 71}; 72 73/* 74 * identifies an elevator type, such as AS or deadline 75 */ 76struct elevator_type 77{ 78 struct list_head list; 79 struct elevator_ops ops; 80 struct elv_fs_entry *elevator_attrs; 81 char elevator_name[ELV_NAME_MAX]; 82 struct module *elevator_owner; 83}; 84 85/* 86 * each queue has an elevator_queue associated with it 87 */ 88struct elevator_queue 89{ 90 struct elevator_ops *ops; 91 void *elevator_data; 92 struct kobject kobj; 93 struct elevator_type *elevator_type; 94 struct mutex sysfs_lock; 95 struct hlist_head *hash; 96 unsigned int registered:1; 97}; 98 99/* 100 * block elevator interface 101 */ 102extern void elv_dispatch_sort(struct request_queue *, struct request *); 103extern void elv_dispatch_add_tail(struct request_queue *, struct request *); 104extern void elv_add_request(struct request_queue *, struct request *, int, int); 105extern void __elv_add_request(struct request_queue *, struct request *, int, int); 106extern void elv_insert(struct request_queue *, struct request *, int); 107extern int elv_merge(struct request_queue *, struct request **, struct bio *); 108extern void elv_merge_requests(struct request_queue *, struct request *, 109 struct request *); 110extern void elv_merged_request(struct request_queue *, struct request *, int); 111extern void elv_bio_merged(struct request_queue *q, struct request *, 112 struct bio *); 113extern void elv_requeue_request(struct request_queue *, struct request *); 114extern int elv_queue_empty(struct request_queue *); 115extern struct request *elv_former_request(struct request_queue *, struct request *); 116extern struct request *elv_latter_request(struct request_queue *, struct request *); 117extern int elv_register_queue(struct request_queue *q); 118extern void elv_unregister_queue(struct request_queue *q); 119extern int elv_may_queue(struct request_queue *, int); 120extern void elv_abort_queue(struct request_queue *); 121extern void elv_completed_request(struct request_queue *, struct request *); 122extern int elv_set_request(struct request_queue *, struct request *, gfp_t); 123extern void elv_put_request(struct request_queue *, struct request *); 124extern void elv_drain_elevator(struct request_queue *); 125 126/* 127 * io scheduler registration 128 */ 129extern void elv_register(struct elevator_type *); 130extern void elv_unregister(struct elevator_type *); 131 132/* 133 * io scheduler sysfs switching 134 */ 135extern ssize_t elv_iosched_show(struct request_queue *, char *); 136extern ssize_t elv_iosched_store(struct request_queue *, const char *, size_t); 137 138extern int elevator_init(struct request_queue *, char *); 139extern void elevator_exit(struct elevator_queue *); 140extern int elevator_change(struct request_queue *, const char *); 141extern int elv_rq_merge_ok(struct request *, struct bio *); 142 143/* 144 * Helper functions. 145 */ 146extern struct request *elv_rb_former_request(struct request_queue *, struct request *); 147extern struct request *elv_rb_latter_request(struct request_queue *, struct request *); 148 149/* 150 * rb support functions. 151 */ 152extern struct request *elv_rb_add(struct rb_root *, struct request *); 153extern void elv_rb_del(struct rb_root *, struct request *); 154extern struct request *elv_rb_find(struct rb_root *, sector_t); 155 156/* 157 * Return values from elevator merger 158 */ 159#define ELEVATOR_NO_MERGE 0 160#define ELEVATOR_FRONT_MERGE 1 161#define ELEVATOR_BACK_MERGE 2 162 163/* 164 * Insertion selection 165 */ 166#define ELEVATOR_INSERT_FRONT 1 167#define ELEVATOR_INSERT_BACK 2 168#define ELEVATOR_INSERT_SORT 3 169#define ELEVATOR_INSERT_REQUEUE 4 170 171/* 172 * return values from elevator_may_queue_fn 173 */ 174enum { 175 ELV_MQUEUE_MAY, 176 ELV_MQUEUE_NO, 177 ELV_MQUEUE_MUST, 178}; 179 180#define rq_end_sector(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq)) 181#define rb_entry_rq(node) rb_entry((node), struct request, rb_node) 182 183/* 184 * Hack to reuse the csd.list list_head as the fifo time holder while 185 * the request is in the io scheduler. Saves an unsigned long in rq. 186 */ 187#define rq_fifo_time(rq) ((unsigned long) (rq)->csd.list.next) 188#define rq_set_fifo_time(rq,exp) ((rq)->csd.list.next = (void *) (exp)) 189#define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist) 190#define rq_fifo_clear(rq) do { \ 191 list_del_init(&(rq)->queuelist); \ 192 INIT_LIST_HEAD(&(rq)->csd.list); \ 193 } while (0) 194 195/* 196 * io context count accounting 197 */ 198#define elv_ioc_count_mod(name, __val) \ 199 do { \ 200 preempt_disable(); \ 201 __get_cpu_var(name) += (__val); \ 202 preempt_enable(); \ 203 } while (0) 204 205#define elv_ioc_count_inc(name) elv_ioc_count_mod(name, 1) 206#define elv_ioc_count_dec(name) elv_ioc_count_mod(name, -1) 207 208#define elv_ioc_count_read(name) \ 209({ \ 210 unsigned long __val = 0; \ 211 int __cpu; \ 212 smp_wmb(); \ 213 for_each_possible_cpu(__cpu) \ 214 __val += per_cpu(name, __cpu); \ 215 __val; \ 216}) 217 218#endif /* CONFIG_BLOCK */ 219#endif 220